This invention relates to fibrous insulation products, and more particularly, to fibrous insulation products having inorganic binders.
Binder materials for fibrous insulation products are well-known. Binder materials hold the individual fibers of a collection of fibers together providing the collection with the integrity to maintain a formed product such as a blanket, mat, bat or panel of insulation material. Binder materials have typically been organic resin materials. Organic resin materials exist in the uncured state as liquids in solution. Thus, they can be easily applied to fibrous materials by spraying or other well-known means. Resin materials can be cured to crosslink the resin and provide strong bonds with the fibrous material. In addition, resin materials can provide thermoplastic properties so that the insulation product may be reheated to allow shaping and processing of the insulation material. These advantages allow cost effective manufacture of fibrous insulation products.
However, organic binder materials are not suitable for all insulation applications. Certain insulation applications require the insulating material to be maintained in an evacuated enclosure. U.S. Pat. No. 5,330,816 to Rusek et al discloses super insulation panels comprising compressed insulating boards in an evacuated jacket. Organic binder materials generally contain volatile organic compounds or VOC's which can be given off slowly over time. Such volatile organic compounds will degrade the level of vacuum in the enclosure and reduce the overall performance of the insulation. Further, certain insulation applications require exposure to high temperatures which can degrade or breakdown an organic binder material. Lastly, organic binder materials may potentially release odors which may be undesirable in some applications.
Accordingly, inorganic binder materials are desired for many applications. Inorganic binder materials have heretofore been known. U.S. Pat. No. 4,833,025 to Rossi discloses inorganic binder materials of silicates, kaolin clay, alumina, zirconia or aluminum phosphate. However, silicate materials, degrade glass fibers on which they are applied. The alkalinity of the silicate compounds causes a breakdown of the individual glass fibers leading to a failure in the insulation product. The remaining compounds, including aluminum phosphate, provide thermosetting properties. That is, these compounds, once solidified, cannot be resoftened to allow additional processing of the insulation material. As a result, they can not be compressed after solidification of the binder for packaging or installation in a compacted state. Thus, the insulation material must be shaped or compressed before solidification. This significantly increases the costs associated with production of insulation having thermoset inorganic binders.
Accordingly, the need remains for an insulation product having an inorganic binder material with thermoplastic properties, which will not degrade at high temperatures, and which will not give off volatile compounds.